Fiber spinning solutions



Patented Oct. 7, 19 52 1 2,613,195 UNITED STATES PATENT OFFICE 2,6Ia195 FIBER SPINNING SOLUTIONS Alfred B. Craig, Dayton, Ohio, assignor, by mesne assignments, .to. The Chemstrand- Corporation, a a corporation of Delaware No Drawing. Application September 26, 1950, Serial No. 186,910

19 Claims. (01. zoo -30.8)

This invention relates to new and valuable fiber spinning solutions. More specifically the invention relates to dispersions of solvents and blended mixtures of acrylonitrile polymers and vinylpyridine polymers which have improved low viscosities and high solid contents.

Itis well-known that polyacrylonitrile and copolymers of acrylonitrile and other polymerizable .mono-olefinic monomers are excellent fiber forming compositions. The polymers of 80 per cent or more acrylonitrile and up to 20 per cent ofother monomers, such as'vinyl acetate, methyl, methacrylate, methyl acrylate, styrene, viny1i-' dene' chloride, and methacryl'onitrile are capable of production into fibers with superior physical properties. Although fibers so prepared have superiortensile properties, desirable elongation, and excellent stability over a wide range of physical and chemical conditions, they are subject to certaininherent disabilities which greatly restrict their utility as general purpose fibers. For example, these compositions and the fibers prepared therefrom do not have sufiicient dye ailinity to enable the development of satisfactory colored fibers. Furthermore many of the compositions are difficult to prepare in suitable solutions due to viscosity increases, gellation and the development of cloudy solutions when conventional fiber spinning procedures are practiced. 3

In copending application, Serial No. 158,332, filed April 126, 1950, by David W. Chaney and Howard M. Home, there are described and claimed new fiber spinningcompositi'ons, which have the desirable fiber properties of the prior art acrylontrilepolymers, but which have unusual receptivity for dyestuffs. In accordance with this procedure the undyeable acrylonitrile polymers are blended with polymers which are inherently better dye acceptors. polymer not only acquires satisfactory dye receptivity but is also found to have an unusuallysuperior thermostability. In'the spinning of the blended polymers it has been found that heterogeneous cloudy solutions, partial gellation, increases in viscosity and other irregularities are frequently encountered.

The fundamental purpose of this invention is to provide means of the improved spinning oi the blended polymers. A further purpose of the invention is to provide a means of reducing the viscosity and increasing the sp inability of the solution without lowering the solid content, and conversely, increasing the solid content of aspinning solution without increasing the viscosity. A

The blended vents for the fiber forming. acrylonitrile polymers to produce solutions ofunusual quality with respect to homogeneity. and, spinability ifthe solutions are made in the presence of minor proportions .of alkyl esters of aromatic sulfonic, acids,

The invention may be practiced with 0.02 to 5.0

per cent by weight of the esters, but preferred practice utilizes from 0.05 1702.0 per cent. Such mixtures have been found to have lower viscosities and complete freedom from turbidity as compared to the same solutions not containingv the alkyl esters of aromatic sulfonic acids. The invention is applicable to blendswherein the principal acrylonitrile polymer is present to the extent of 50 to 98 per cent by weight, and the copolymer is one of or more per cent of acrylonitrile and minor proportions of monomers copolymerizable therewith. The other compo-- nent of the blend is a polyvinylpyridine or a copolymer of 30 or more per cent ofvinylpyridine orv alkyl substituted vinylpyridineand up to -70,

per cent of another copolymerizable monomer. The two; components of the blended copolymers are proportioned so as to provide a total of from two to ten per cent of vinylpyridine in polymeric form in the blended composition.

Useful vinylpyridines for the preparation of the blending composition are vinylpyridine or alkyl substituted vinylpyridine, for example ,2-vinylpyridine; 3-vinylpyridine, ,4-vinylpyridine, 2- vinyl-4-ethylpyridine, 2-vinyl-3-methylpyridine, 5- vinyl 2-methylpyridine, 2-vinyl-5-ethylpyridine, 2-vinyl-4-methylpyridine, 3-vinyl-5-ethylpyridine, and any other vinylpyridine containing alkyl substituents wherein the alkyl radical has up to four carbon atoms.

The dyeable blended copolymers may have in addition to the functional components, acrylonitrile and vinylpyridine, one or more components derived from monomers, such as vinyl acetate, and other vinyl esters or carboxylic acids having up to four carbon atoms, vinylchloroacetate, methyl methacrylate, methyl acrylate and other alkyl acrylates and alkyl methacrylates wherein the alkyl radical has up to four carbon atoms, diethyl maleate; diethyl fumarate and other alkyl maleates and iumarates wherein the.

alkyl radical has up to four carbon'atoms, styrene, and other vinyl substituted aromatic hydrocarbons, vinylidene chloride and methacrylonitrile. These non-functional monomers may be present as a comonomer with'acrylonitrile in the 1 known to the art. Of particular utility arethe emulsion or dispersion polymerizations which place at elevated temperatures utilizing reflux conditions to eliminate the heat of polymerization or the reaction may be conducted by the Redox methods in lower temperatures. I ventional to use regulators, for example the various mercaptans, such as tertiary-dodecyl mercaptan, mercapto acetic acid, and the esters of mercapto acetic acid. The separation of the acrylonitrile polymers from the aqueous medium may be accomplished by filtration or decantation followed by drying in the manner well-known to the art.

The vinylpyridine polymers may be by mass polymerization methods, solution polymerization methods or aqueous emulsion procedures, the latter being the preferred manner of preparation. The preferred procedure involves the use of efficient emulsion stabilizing agents for the purpose of preventing agglomeration of the polymer particles. The details of polymerization procedure and separation of the polymer from the reaction medium may be practiced by any of the numerous methods known to the art.

The fiber forming acrylonitrile polymer and vinylpyridine polymers are physically blended by a wide variety of procedures. If desired the emulsions or dispersions of polymers in aqueous media, just as received from the polymerization reactors may be blended. Physical mixtures of the separated solid polymers may also be utilized. A preferred manner of preparing the mixtures involves the dispersion of the polymers, or the emulsions thereof in a solvent, with the distillation or evaporation of the water, if present in proportions large enough to interfere with the complete dissolution of the solid polymers. In the preparation of the blends in the presence of a conventional solvent, or preferably N,N-dimethylacetamide, from which the fiber spinning willultimately take place, frequently non-homogeneous, cloudydispersions are obtained.

' The invention may also be practiced with other solvents for fiber forming acrylonitrile polymers, for example N',N-dimethylformamide, ethylene carbonate, butyrolactone, a-cyanoacetamide, maleic anhydride, succinic anhydride, and N,N-dimethylmethoxyacetamide.

In accordance with the practice of this invention minor proportions of alkyl esters of aromatic sulfonic acids are added. It has been found that from 0.02to 5.0 per cent by weight (based on the solution) will eliminate the turbidity and produce clear, transparent, light-colored polymer solutions. The treatment has also been found to cause a marked reduction in viscosity, thereby enabling the spinning with the higher solid content in the spinning solutions or spinning at lower temperatures than otherwise would be required. Improvements in dye receptivity and dye fastness were noted.

Further details of the invention are set forth with respect to the following specific examples:

Example 1 cent acrylonitrile and 50 per cent vinylpyridine It is also con-.

were added thereto and the mixture stirred for one hour at C. A clear homogeneous solution containing 1.03 per cent of methyl toluenesulfonate resulted. The temperature was then lowered to 65 C. which was maintained for twelve hours.

The solution, was then extruded through a spinnereti having 30 apertures each 0.05 inch in diameter. The fibers were extruded into a spin bath comprised of 60 parts of N,N-dimethylacetamide and 40 parts of water. The fibers were stretched 600 per cent, washed, and dried.

The fibers were found to exhaust a dye bath comprised of one ml. of a two per cent aqueous solution of Wool Scarlet G Supra dye, five cc. of three per cent sulfuric acid, and 40 cc. of water for each gram of fiber being dyed.

Example 2 A fiber spinning solution was prepared by mixing an aqueous dispersion containing 115.5 grams of a copolymer of 97 per cent acrylonitrile and three per cent of vinyl acetate, 10.5 grams of a copolymer of 50 per cent vinyl acetate and 50 per cent vinylpyridine, and 624 grams of N,N-dimethylacetamide. The preparation of the mixture involved stirring for one and one-half hours at 80 to C. The spinning solution so prepared was divided into two parts and one portion was treated with one per cent by weight of methyl toluenesulfonate. Both solutions were then aged for twelve hours at 60 C. The viscosity of each solution was measured at 50 C. using a Brookfield viscometer. The untreated solution was found to have a viscosity of 216 poises, whereas the sample treated with methyl toluenesulfonate had a viscosity of only 160 poises.

Example 3 The procedure of the preceding experiments was repeated except that the spinning solutions were prepared from 637.5 grams of N,N-dimethylacetamide, 13.0 grams of a copolymer of 30 per cent acrylonitrile and 70 per cent vinylpyridine, 99.5 grams of a copolymer of per cent acrylonitrile and five per cent vinyl acetate and 0.8 gram of methyl toluenesulfonate. The methyl toluenesulfonate amounted to 0.106 per cent by weight of the resulting solution. The solutions were readily spun into stron dyeable fibers.

Eznample 4 Example 5 A fiber spinning solution the same as described in the preceding example except that only 0.4 gram of methyl toluenesulfonate was used. This solution contained methyl toluenesulfonate in the amount of 0.053 per cent by. weight of the resulting solution. This solution was also stabilized with respect to viscosity and was useful in the preparation of synthetic fibers.

The invention is claims.

defined by the following What I claim is:

1. A fiber spinning solution comprising a solvent for fiber-forming acrylonitrile polymers, a blend of a polymer of at least 90 per cent acrylonitrile and a polymer of at least 30 per cent vinylpyridine, said polymers being so proportioned so as to provide a total of from two to ten per cent of vinylpyridine in polymeric form in the blended polymer, and from 0.02 to 5.0 per cent by Weight (based on the solution) of an alkyl ester of an aromatic sulfonic acid.

2. The product of claim 1 wherein the alkyl ester is methyl toluenesulfonate.

3. The product of claim 1 wherein the alkyl ester is ethyl toluenesulfonate.

4. The product of claim 1 wherein the allcyl ester is ethyl benzenesulfonate.

5. The product of claim 1 wherein the alkyl ester is methyl benzenesulfonate.

6. The product of claim 1 wherein the alkyl ester is methyl dodecylbenzenesulfonate.

7. A fiber spinning composition comprising a N,N-dimethylacetamide solution of a blend of a polymer of at least 90 per cent acrylonitrile and a polymer of at least 30 per cent vinylpyridine, said polymers being blended in such proportions so as to produce polymer having from two to 8. The product of claim '1 wherein the alky ester is methyl toluenesulfonate.

9. The product of claim '7 wherein the alkyl ester is ethyl toluenesulfonate.

10. The product of claim 7 wherein the alkyl ester is ethyl benzenesulfonate.

11. The product of claim 7 wherein the alkyl ester is methyl benzenesulfonate.

12. The product of claim 7 wherein the alkyl ester is methyl dodecylbenzenesulfonate.

13. A fiber spinning solution comprising a. solvent for fiber-forming acrylonitrile polymers, a blend of a polymer of at least 90 per cent acrylonitrile and up to ten per cent of a monomer of the group consisting of vinyl acetate and other vinyl esters of carboxylic acids having up to four carbon atoms, vinylchloroacetate, methyl methacrylate, methyl acrylate, other alkyl acrylates and methacrylates wherein the alkyl radical has up to four carbon atoms, styrene and other vinyl substituted aromatic hydrocarbons,

maleate, other alkyl fumarates and alkyl maleates wherein the alkyl radical has up to four carbon atoms and methacrylonitrile; and a poly mer of at least 30 per cent of vinylpyridine and up to '70 per cent of acrylonitrile; and from 0.02 to 5.0 per cent by weight (based on the solution) of an alkyl ester of an aromatic sulionic acid, said blended polymers being so proportioned as to provide between two and ten per cent of vinylpyridine in polymeric form.

14. A fiber spinning composition comprising a N,N-diniethylacetamide solution of a blend of a polymer of at least 90 per cent acrylonitrile and up to ten per cent of a monomer of the group consisting of vinyl acetate and other vinyl esters of carboxylic acids having up to four carbon atoms, vinylchloroacetate, methyl methacrylate, methyl acrylate, other alkyl acrylates and methacrylates wherein the alkyl radical has up to four carbon atoms, styrene, other vinyl substituted aromatic hydrocarbons, vinylidene chloride, diethyl fumarate, diethyl maleate, other alkyl fumarates and alkyl maleates, wherein the alkyl radical has up to four carbon atoms and methacrylonitrile; and a polymer of at least 30 per cent of vinylpyridine and up to per cent of acrylonitrile; and from 0.05 to 2.0 per cent by Weight (based on the solution) of an alkyl ester of an aromatic sulfonic acid, said blended polymers being so proportioned as to provide between two and ten per cent of vinylpyridine in polymeric form.

15. The product of claim 14 wherein the alkyl ester is methyl toluenesulfonate.

16. The product of claim 14 wherein the alkyl ester is ethyl toluenesulfonate.

17. The product of claim 14 wherein the alkyl ester is ethyl benzenesulfonate.

18. The product of claim 14 wherein the alkyl ester is methyl benzenesulfonate.

19. The product of claim 14 wherein the alkyl ester is methyl dodecylbenzenesulfonate.

ALFRED B. CRAIG.

REFERENCES CITED UNITED STATES PATENTS Name Date Coover et a1 Apr. 11, 1950 Number 

1. A FIBER SPINNING SOLUTION COMPRISING A SOL VENT FOR FIBER-FORMING ACRYLONITRILE POLYMERS, A BLEND OF A POLYMER OF AT LEAST 90 PER CENT ACRYLONITRILE AND A POLYMER OF AT LEAST 30 PER CENT VINYLPYRIDINE, SAID POLYMERS BEING SO PROPORTIONED SO AS TO PROVIDE A TOTAL OF FROM TWO TO TEN PER CENT OF VINYLPYRIDINE IN POLYMERIC FORM IN THE BLENDED POLYMER, AND FROM 0.02 TO 5.0 PER CENT BY WEIGHT (BASED ON THE SOLUTION) OF AN ALKYL ESTER OF AN AROMATIC SULFONIC ACID. 